1. Field of the Invention
Illustrative embodiments of the present disclosure relate to a device capable of reducing bulging of a saddle-stitched booklet or a bundle of two-folded sheets, a system or device built into a folding device or a saddle-stitching device, a spine formation device that is built into a post processing device connected to the foregoing system or device to perform post processing, such as cutting, on a bound book and forms a spine of the bound book, and a system or apparatus including the spine formation device.
2. Description of the Background
As a technique for straightening the spine of a booklet, for example, a conventional approach like that described in JP-2001-260564-A is known. The conventional apparatus includes a clamping unit disposed to hold and fix a bundle of sheets (hereinafter “booklet”), folded so that a spine portion of the booklet protrudes from the clamp unit, and a spine forming unit movable in a longitudinal direction of the spine portion of the booklet to press the spine and flatten it. By using the clamping unit and the spine forming unit, the spine of the booklet is flattened (deformed) to reduce bulging of the booklet. This reformation is important for ease of storage and transport because the curved spine causes the booklets to bulge and bulging booklets can be difficult to stack, making it difficult to store or carry them. In the above-mentioned approach, such bulging is reduced by flattening the spine of the booklet so as to eliminate such inconvenience.
The above-described approach is now described in further detail with reference to FIGS. 11-13. It can be seen that the amount by which the spine protrudes from the clamping unit 12 is regulated by a flat stopper 14. However, in such a configuration, the sheets are freely movable in a space between the clamping unit 12 and the stopper 14 as shown in FIGS. 11 and 12. Consequently, during positioning, a folded portion of the booklet 13 may shift position as indicated by a circle area “A” illustrated in FIG. 11. If the clamping unit 12 clamps the booklet 13 and flattens the spine of the booklet 13 with a spine forming unit 18, the spine may be deformed in an irregular shape as illustrated in FIG. 12.
The spine forming unit 18 is movable in the longitudinal direction of the protruding portion of the booklet and applies enough pressure to the spine to flatten the curvature of the spine. Although controlled during spine formation, the pressure needed to flatten the curvature of the spine fluctuates continuously and substantially. Consequently, the distance between the spine forming unit 18 and the booklet also continuously fluctuates, thus preventing the spine from being flattened. In fact, as indicated by a portion “B” illustrated in FIG. 13, the spine may be made wavy rather than straight, thus detracting from the booklet's appearance.